Theodoe richters



NITED STATES PATENT OFFICE.

THEODOR RIGHTERS,'OF BRESLAU, PRUSSIA, GERMANY.

MANUFACTURE OF POTASSIUM FERROCYANIDE.

SPECIFICATION forming part of Letters Patent No. 245,661, dated August 16, 1881.

Application filed October 25, 1880. (No specimens.) Patented in France September 20, 1880. and in Belgium September 20, 1880.

To all whom it may concern Be it known that I, THEODOR RIcH'rERs, ot' Breslau, in the Kingdom of Prussia, Germany, have invented a new and useful Process for Obtaining Prussiate ofPotash, Ammonia, Tar, and Gas from Nitrogcnous Substances, of which the following is a specification.

- The object of my invention is to obtain prussiate of potash, ammonia, tar, and gas from all kinds of nitrogenous substances; and for this purpose I mix the substances with carbonate of potassium, which will bealways recovered again at the end of the operation.

The process is as follows: I moisten the azotized substances-such as old leather, fresh or dried blood, horn, hair, feathers, fur, felt, or cloth, &c.-with a solution of carbonate of potassium and then dry on a kiln below the tem perature of combustion. The kiln must be constructed so that carbonic acid comes in contact with the substances to be dried, or the solution of carbonate of potassium can be made free of caustic potash before the moistenin g of the substances by introducing carbonic acid. When the substances are very sandy it is necessary to get rid of the sand by washing with lye of potash before the drying. The welldried substances are then transformed into gas in any convenient apparatus. Their-fusion is not necessary. The escaping ammonia,

carbonate of potassium, sulphuret of potassium, caustic potash, and carbon. By lixiviating and boiling with metallic iron or peroXide of iron, the cyanide of potassium is changed into prussiateof pot-ash and caustic potash. The solution is then evaporated and the prussiate'ot' potash separated therefrom in any convenient manner. The remaining lye contains principally carbonate of potash and caustic potash, and is used again for moistening other nitrogenous substances.

The caustic potash is transformed into carbonate of potash during the drying manipulation.

Having now fully described my invention, what I claim as my invention, and desire to secure by Letters Patent, is

The herein-described process of obtaining prussiate ot' potash, &c., consisting in moistening nitrogenous substances with carbonate of potash, or a mixture (substantially as described) containing the same; then drying them without combustion while in contact with carbonic acid; then beating them sufficiently in a retort or other suitable vessel to gasify and drive oft all volatile ingredients, then washing or boiling the residuum with iron, and, finally, separating the prussiate ot' potash from said solution in any convenient manner.

THEODOR RIGHTERS. Witnesses:

EMIL E. HAASE, FRANZ PoRzAWKA. 

